This is true. Force of habit I guess, a lot of schemas I've worked on mix all the constructs for various reasons. For example, I'll often see element nodes as sisters of the choice nodes, and doing this is often accomplished in a sequence...
-BKN
----- Original Message -----
From: Pete Hendry
To: Bryce K. Nielsen
Cc: xmlschema-dev@w3.org
Sent: Monday, March 21, 2005 10:39 PM
Subject: Re: Either-Or elements
What does the sequence add?
<xsd:complexType name="somethingType">
<xsd:choice minOccurs="1" maxOccurs="1">
<xsd:element name="foo"/>
<xsd:element name="bar"/>
</xsd:choice>
</xsd:complexType>
or more simply
<xsd:complexType name="somethingType">
<xsd:choice>
<xsd:element name="foo"/>
<xsd:element name="bar"/>
</xsd:choice>
</xsd:complexType>
Pete
Bryce K. Nielsen wrote:
You'll want to use the xsd:choice node. i.e.:
<xsd:complexType name="somethingType">
<xsd:sequence minOccurs="1" maxOccurs="1">
<xsd:choice>
<xsd:element name="foo"/>
<xsd:element name="bar"/>
</xsd:choice>
</xsd:sequence>
</xsd:complexType>
By nesting the xsd:choice within a xsd:sequence node allows you to force how many times this "choice" is allowed. From your sample schema, it seemed like you only wanted it to occur once, thus the min/max in the sequence...
HTH,
Bryce K. Nielsen
SysOnyx, Inc. (www.sysonyx.com)
Makers of xmlDraft, the Smart XSD Editor
http://www.sysonyx.com/products/xmldraft
----- Original Message -----
From: RPearse@360commerce.com
To: xmlschema-dev@w3.org
Sent: Monday, March 21, 2005 12:02 PM
Subject: Either-Or elements
Using a DTD, I can specify that the something element can only have foo or bar, but not both with this: <!ELEMENT something ((foo|bar)*)>
In an XSD, I would have this:
<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsd:element name="something" type="somethingType" />
<xsd:complexType name="somethingType">
<xsd:sequence>
<xsd:element name="foo" minOccurs="1" maxOccurs="1" />
<xsd:element name="bar" minOccurs="1" maxOccurs="1" />
</xsd:sequence>
</xsd:complexType>
How would I specify that the user has to have the foo or bar element, but not both? Currently, this XSD seems to require that you have exactly one foo and one bar in your instance document.
Thanks,
Robert